This invention relates to an improvement of cerebral aneurysm clamps or clips.
Several types of cerebral aneurysm clips are known in the art. It is true that these conventional cerebral aneurysm clips have their own specific features. However, they do not satisfy all the conditions required for their use.
The cerebral aneurysm clip is a surgical instrument for clamping the base part of a cerebral aneurysm to permanently isolate the latter from the cerebral artery, and therefore it must be able to continuously maintain its clamping state with high reliability.
Since the operation for clipping a cerebral aneurysm is an extremely delicate one which is carried out at a deep, narrow part of the brain by optically magnifying affected part with a microscope, the cerebral aneurysm clip must satisfy the following conditions (1) through (5):
(1) The clamping pressure of the clip must be suitable for permanently isolating a cerebral aneurysm and for preventing the clip from being displaced or slipped off. As the clip can also be used for temporarily blocking the flow of blood in a normal blood vessel, the clamping pressure of the clip should not be so great as to give damage to a blood vessel, that is, it must be a certain pressure suitable for temporarily blocking the flow of blood. PA1 (2) The opening degree of the clamping jaws of the clip must be greater than the size of a cerebral aneurysm, that is, it must be great enough to clamp the cerebral aneurysm. PA1 (3) Since the clip is normally left permanently in the brain, the size of the clip must be as small as possible. PA1 (4) In addition, the shape of the clip must be such that when clamping a cerebral aneurysm the operator can clearly see it without being blinded by the clip. PA1 (5) The width of the jaws of the clip must be so small that the jaws can clamp a cerebral aneurysm across the narrow base part thereof.
In conventional cerebral aneurysm clips, it has sometimes experienced that they are displaced improperly from a desired clamping position and in the worst case they are slipped off the base part of a cerebral aneurysm to which they are applied. This is a serious problem because if the clip applied is slipped off it influences a human life.